Problem 116
Calculate \(Q\) and \(W\) for the isothermal reversible expansion of one mole of an ideal gas from an initial pressure of \(1.0\) bar to a final pressure of \(0.1\) bar at a constant temperature of \(273 \mathrm{~K}\). (a) \(5.22 \mathrm{~kJ},-5.22 \mathrm{~kJ}\) (b) \(-27.3 \mathrm{~kJ}, 27.3 \mathrm{~kJ}\) (c) \(27.3 \mathrm{~kJ},-27.3 \mathrm{~kJ}\) (d) \(-5.22 \mathrm{~kJ}, 5.22 \mathrm{~kJ}\)
Problem 117
If at \(298 \mathrm{~K}\) the bond energies of \(\mathrm{C}-\mathrm{H}, \mathrm{C}-\mathrm{C}, \mathrm{C}=\mathrm{C}\) and \(\mathrm{H}-\mathrm{H}\) bonds are respectively \(414,347,615\) and \(435 \mathrm{~kJ}\) \(\mathrm{mol}^{-1}\), the value of enthalpy change for the reaction \(\mathrm{H}_{2} \mathrm{C}=\mathrm{CH}_{2}(\mathrm{~g})+\mathrm{H}_{2}(\mathrm{~g}) \longrightarrow \mathrm{H}_{3} \mathrm{C}-\mathrm{CH}_{3}(\mathrm{~g})\) at \(298 \mathrm{~K}\) will be: (a) \(+250 \mathrm{~kJ}\) (b) \(-250 \mathrm{~kJ}\) (c) \(+125 \mathrm{~kJ}\) (d) \(-125 \mathrm{~kJ}\)
Problem 118
An ideal gas expands in volume from \(1 \times 10^{-3} \mathrm{~m}^{3}\) to \(1 \times 10^{-2} \mathrm{~m}^{3}\) at \(300 \mathrm{~K}\) against a constant pressure of \(1 \times 10^{5} \mathrm{Nm}^{-2}\). The work done is: (a) \(-900 \mathrm{~kJ}\) (b) \(-900 \mathrm{~J}\) (c) \(270 \mathrm{~kJ}\) (d) \(940 \mathrm{~kJ}\)
Problem 119
The enthalpies of combustion of carbon and carbon monoxide are \(-393.5\) and \(-283 \mathrm{~kJ} \mathrm{~mol}^{-1}\) respectively. The enthalpy of formation of carbon monoxide per mole is: (a) \(-676.5 \mathrm{~kJ}\) (b) \(-110.5 \mathrm{~kJ}\) (c) \(110.5 \mathrm{~kJ}\) (d) \(676.5 \mathrm{~kJ}\)
Problem 120
If the bond dissociation energies of \(\mathrm{XY}, \mathrm{X}_{2}\) and \(\mathrm{Y}_{2}\) are in the ratio of \(1: 1: 0.5\) and \(\Delta \mathrm{H}_{\mathrm{f}}\) for the formation of \(\mathrm{XY}\) is \(-200 \mathrm{~kJ} / \mathrm{mole}\). The bond dissociation energy of \(\mathrm{X}_{2}\) will be: (a) \(100 \mathrm{~kJ} / \mathrm{mole}\) (b) \(400 \mathrm{~kJ} / \mathrm{mole}\) (c) \(600 \mathrm{~kJ} / \mathrm{mole}\) (d) \(800 \mathrm{~kJ} / \mathrm{mole}\)
Problem 122
The enthalpy changes for the following processes are listed below. \(\mathrm{Cl}_{2}(\mathrm{~g})=2 \mathrm{Cl}(\mathrm{g}) ; 242.3 \mathrm{~kJ} \mathrm{~mol}^{-1}\) \(\mathrm{I}_{2}(\mathrm{~g})=21(\mathrm{~g}) ; 151.0 \mathrm{~kJ} \mathrm{~mol}^{-1}\) \(\mathrm{ICl}(\mathrm{g})=\mathrm{I}(\mathrm{g})+\mathrm{Cl}(\mathrm{g}) ; 211.3 \mathrm{~kJ} \mathrm{~mol}^{-1}\) \(\mathrm{I}_{2}(\mathrm{~s})=\mathrm{I}_{2}(\mathrm{~g}) ; 62.76 \mathrm{~kJ} \mathrm{~mol}^{-1}\) Given that the standard states for iodine and chlorine are \(\mathrm{I}_{2}(\mathrm{~s})\) and \(\mathrm{Cl},(\mathrm{g})\), the standard enthalpy of formation for \(\mathrm{ICl}(\mathrm{g})\) is: (a) \(-14.6 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (b) \(-16.8 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (c) \(+16.8 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (d) \(+244.8 \mathrm{~kJ} \mathrm{~mol}^{-1}\)
Problem 123
In the conversion of lime stone to lime, \(\mathrm{CaCO}_{3}(\mathrm{~s}) \longrightarrow \mathrm{CaO}(\mathrm{s})+\mathrm{CO}_{2}(\mathrm{~g})\) The values of \(\Delta \mathrm{H}^{\circ}\) and \(\Delta \mathrm{S}^{\circ}\) are \(+179.1 \mathrm{~kJ} \mathrm{~mol}^{-1}\) and \(160.2 \mathrm{~J} / \mathrm{K}\) respectively at \(298 \mathrm{~K}\) and 1 bar. Assuming that \(\Delta \mathrm{H}^{\circ}\) and \(\Delta \mathrm{S}^{\circ}\) do not change with temperature, temperature above which conversion of limestone to lime will be spontaneous is: (a) \(1200 \mathrm{~K}\) (b) \(845 \mathrm{~K}\) (c) \(1118 \mathrm{~K}\) (d) \(1008 \mathrm{~K}\)
Problem 124
Standard entropy of \(\mathrm{X}_{2}, \mathrm{Y}_{2}\) and \(\mathrm{XY}_{3}\) are 60,40 and 50 \(\mathrm{JK}^{-1} \mathrm{~mol}^{-1}\), respectively. For the reaction: \(1 / 2 \mathrm{X}_{2}+3 / 2 \mathrm{Y}_{2} \longrightarrow \mathrm{XY}_{3}, \Delta \mathrm{H}=-30 \mathrm{~kJ}\), to be at equilibrium, the temperature will be: (a) \(1250 \mathrm{~K}\) (b) \(500 \mathrm{~K}\) (c) \(750 \mathrm{~K}\) (d) \(1000 \mathrm{~K}\)
Problem 125
Oxidizing power of chlorine in aqueous solution can be determined by the parameters indicated below: \(\frac{1}{2} \mathrm{Cl}_{2}(\mathrm{~g}) \frac{1 / 2 \Delta_{\mathrm{diss}} \mathrm{H}}{\longrightarrow} \mathrm{Cl}(\mathrm{g}) \stackrel{\Delta_{\mathrm{cg}} \mathrm{H}^{-}}{\longrightarrow}\) \(\mathrm{Cl}\) (g) \(\stackrel{\Delta_{\text {hyd. }} \mathrm{H}}{\longrightarrow} \mathrm{Cl}^{-}\) (aq) The energy involved in the conversion of \(\frac{1}{2} \mathrm{Cl}_{2}\) (g) to \(\mathrm{Cl}^{-}(\mathrm{g})\) (Using the data, \(\Delta_{\text {diss }} \mathrm{H} \mathrm{Cl}_{2}=240 \mathrm{~kJ} \mathrm{~mol}^{-1}, \Delta_{\mathrm{eg}} \mathrm{H} \mathrm{Cl}\) \(\left.=-349 \mathrm{~kJ} \mathrm{~mol}^{-1}, \Delta_{\text {hyd }} \mathrm{H} \mathrm{Cl}^{2}=-381 \mathrm{~kJ} \mathrm{~mol}^{-1}\right)\) will be: (a) \(+152 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (b) \(-610 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (c) \(-850 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (d) \(+120 \mathrm{~kJ} \mathrm{~mol}^{-1}\)
Problem 126
10 mole of an ideal gas expand isothermally and reversibly from a pressure of 10 atm to 1 atm at \(27^{\circ} \mathrm{C}\). What will be the largest mass that be lifted through a height of 100 metre? (a) \(5.855 \mathrm{Kg}\) (b) \(58.55 \mathrm{Kg}\) (c) \(585.5 \mathrm{Kg}\) (d) \(29.28 \mathrm{Kg}\)
